<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<script>
			function getsum(){
				console.log(arguments.length);
				console.log(arguments);
				var sum=0;
				for (var i in arguments) {
					sum+=arguments[i];
				}
				return sum;
			}
			function css(){
				if (arguments.length==2) {
					return arguments[0].style[arguments[1]];
				} else if (arguments.length==3) {
					arguments[0].style[arguments[1]]=arguments[2];
				
				} else{
					alert("no");
				}{
					
				}
			}
			window.onload=function(){
				var div1=document.getElementById('div1');
				alert(css(div1,'width'));
				css(div1,'background','blue');
			}
		</script>
		<div id="div1" style="width: 200px;background: rgb(153,217,234);height: 200px;"></div>
	</body>
</html>
